1. Technical Field
The present invention relates to a contact structure between a pair of contacts that respectively establish live connections with electrical circuits, and more specifically, relates to a contact structure for a pair of contacts that contact and separate from each other and between which a high electrical energy occurs.
2. Related Art
An electrical connector that establishes a live connection for an electric power line that transmits high voltage, high current electric power or the like accumulates a high electrical energy between a pair of adjoining contacts when a correspondingly formed connector connected is inserted and drawn out, and arcing occurs therebetween. Such arcing occurs also due to an induced electromotive force generated when one connector connected to an inductive load is drawn out of another connector connected to an electric power line.
Conventionally, there have been measures taken against arcing because it becomes a cause of accelerated degradation of a contact of an electrical connector due to erosion of it or the like, and such measures are generally classified into two methods. In a first method, which is exemplified by a method disclosed in Japanese Patent Application Publication No. 2010-56055 (Patent Document 1), a permanent magnet or the like is arranged in a direction orthogonal to a direction in which a pair of contacts face each other to apply a magnetic field, and the direction of arcing is deflected by a Lorentz force to prevent damages to the contact due to arcing.
Also, a second method is a method by which arcing is prevented from occurring by lowering an electrical energy itself accumulated between a pair of contacts. Because the electrical energy accumulated between a pair of contacts is proportional to the voltage and current between the pair of contacts, in Japanese Patent Application Publication No. S63-86281 (Patent Document 2) and Japanese Utility Model Application Publication No. H4-2467 (Patent Document 3), occurrence of arcing is prevented by lowering the voltage between a pair of contacts when the contacts separate.
That is, in a contact structure 100 described in Patent Document 2, as shown in FIG. 8, a contact 101 and a resistor 102 having an electrical resistivity ρ higher than that of the contact 101 are provided continuously along a movement path along which a contact 103 of a correspondingly formed connector moves, and when the other contact 103 is drawn out of and separate from the movement path, the contact 103 is separated at a leading edge 102a of the resistor 102 having the highest resistance value, thereby making the voltage between them a voltage that does not cause arcing, so as to prevent occurrence of arcing.
Also, in a contact structure 110 described in Patent Document 3, as shown in FIGS. 9A and 9B, the resistance value of a contact 112 is made higher at positions farther in the separation direction (rightward in the figure) along a movement path along which a correspondingly formed contact 114 moves. When the correspondingly formed contact 114 initially inserted completely as shown in FIG. 9A is drawn out of the movement path as shown in FIG. 9B, a significant potential drop is caused to the contact 112 by making the highest the resistance of the portion of a leading edge 112a of the contact 112 which the contact 114 adjoins, thereby making the voltage between the leading edge 112a and the contact 114 a voltage that does not cause arcing.